Spectral dependence of negative photoconductivity

A theoretical analysis is made of the condition for the appearance of the negative photoconductivity, and its spectral characteristics are considered. An expression is obtained for the dependence of the photoelectron density on the frequency of the exciting light. It is shown that the photoconductivity spectra can be used to determine the dopant concentration. The negative photoconductivity may find applications in optoelectronics and other branches of semiconductor laser technology. Moreover, experimental studies of the negative photoconductivity spectra may give information on the validity of various models used in calculations of the laser gain in heavily doped semiconductors.